Baby Sharks Can Sense Danger, Even Before They’re Born

Before they even leave their eggs, embryonic bamboo sharks freeze in response to perceived danger – a behavior that may help scientists develop a more effective shark repellent.

The still-developing bamboo sharks are responding to electrical fields generated by predators, a study published today in PLoS ONE reports.

Bamboo sharks live in shallow, west Pacific waters and can grow up to 3.5 feet long. Unlike some other shark species, they don’t give birth to live young. Instead, embryos develop in eggs, taking as long as five months to reach hatching age. During that time, the egg-enclosed sharks are vulnerable to predation by large fishes and other sharks, which can sense the odors, water flow, and electric field produced by thrashing tails and moving gills.